1. Field of the Invention
The present invention relates to a method of manufacturing a reinforcing cloth of a seat pad and an apparatus therefor, especially for a seat of a vehicular seat.
2. Related Background of the Invention
For a vehicular seat, there is used a seat pad, in which a urethane resin or the like is foamed as a cushioning material (as described in Japanese unexamined patent publication No. Hei. 5-130923). In addition to the foamed urethane resin, another cushioning material of a fibrous cushioning material is also proposed (as described in Japanese unexamined patent publication No. Hei. 10-291267). The fibrous cushioning material is made from fiber webs including high melting point fibers as base fibers and low melting point fibers as binder fibers.
A seat pad coated with a cloth or a skin provides a surface for supporting a passenger on the front surface side, and the rear surface side of the seat pad is mounted on a support member such as a pipe frame or a spring so that the seat pad constructs a sheet of a vehicular seat. Since at least a part of the rear surface of the seat pad rubs the support member by vibrations of the vehicle and the body motion of the passenger or the like, the seat pad is easily damaged. Therefore, conventionally, a reinforcing cloth as a reinforcing layer is provided on the rear surface of the seat pad.
The reinforcing cloth of the seat pad protects the seat pad against the damage so that it is so formed integrally with the seat pad as not to slip on or peel off the seat pad. Therefore, for the foaming and shaping steps for manufacturing the seat pad, there is adopted a method including the step of injecting and foaming a resin into the mold with the reinforcing cloth being set in advance on the inner surface of the mold and the step of simultaneously performing the shaping of the seat pad and the forming of a reinforcing layer.
Since the rear surface of the seat pad has a complicated shape (e.g., roundabout portions 14 and 15 shown in FIG. 9 and FIG. 10), conventionally, the reinforcing cloth is formed by sewing a number of small pieces in order to match the complicated shape. However, such a seat pad has problems that the cutting and the sewing take many labors and require long time to manufacture. Moreover, there is another problem that it is difficult to fit the reinforcing cloth into the shape of an inner surface of a mold precisely. In order to solve these problems, therefore, there is proposed a method of manufacturing the reinforcing cloth by molding a nonwoven fabric as described in Japanese unexamined patent publication No. Hei. 5-130923.
As a nonwoven fabric used for a reinforcing cloth of a seat pad, other structures has been proposed as described in Japanese unexamined patent publications No. Hei. 5-138782 and 2000-62061. In these publications, an air-impermeable plastic film is mounted on the nonwoven fabric, or a layer of a different apparent density is laminated, in order to prevent the exudation of a resin during foaming and shaping steps.